buatlah persamaan garis dibawah ini ! 1) melalui titik A(3,1) , dan B(-2,5)

Bab Persamaan Garis
Matematika SMP Kelas VIII

(y - y1) / (y2 - y1) = (x - x1) / (x2 - x1)
(y - 1) / (5 - 1) = (x - 3) / (-2 - 3)
(-5) (y - 1) = 4 (x - 3)
-5y + 6 = 4x - 12
4x + 5y = 6 + 12
4x + 5y = 18

Jawab :

m : y2 - y1/ x2 - x1 = 5 - 1/(-2) - 3 = - 4/5

y - y1 = m(x - x1)
y - 1 = - 4/5 (x - 3)
y - 1 = - 4/5x + 4/5 . 3
y - 1 = - 4/5x + 12/5
------------------------------ x 5
5. y - 1 . 5 = - 4/5x . 5 + 12/5 . 5

5y - 5 = -4x + 12
5y - 5 + 4x - 12 = 0
5y + 4x - 17 = 0
4x + 5y - 17 = 0 => ax + by + c = 0